Power press

ABSTRACT

Generally speaking, the present invention contemplates a pneumatic power press tool having an elongated cylindrical piston assembly with an upper impact air port at the upper end of said assembly, and an impact piston within said assembly, acted upon by compressed air fed through said impact air port. There is an outer housing cylinder with said assembly being radially disposed and longitudinally displaceable therein. A cylinder stroke locking plate is disposed above and parallel to the top wall. Passing through the top wall is an adjustment locking rod, including locking means to lock said locking rod at desired locations. A cylinder stroke adjuster disc is adjustably held by said locking rod and defines a stroke limit within the outer housing cylinder. Connected to the outside of said piston assembly is an outer piston disc and this piston disc moves longitudinally within said outer housing cylinder between the stroke adjuster disc and bottom wall. The outer piston disc is activated by a pneumatic arrangement feeding compressed air to the outer piston disc through the stroke adjuster disc. Thus, the outer piston disc provides a first stroke and the impact piston provides a second stroke, the length and quantity of air fed to the first stroke being adjustable.

United States Patent Koches et al.

1 1 Mar. 14, 1972 Primary ExaminerEdgar W. Geoghegan Assistant ExaminerLeslie .l. Payne Attorney-George B. Oujevolk [57] ABSTRACT Generally speaking, the present invention contemplates a pneumatic power press tool having an elongated cylindrical piston assembly with an upper impact air port at the upper end of said assembly, and an impact piston; within said assembly, acted upon by compressed air fed through said impact air port. There is an outer housing cylinder with said assembly being radially disposed and longitudinally displaceable therein. A cylinder stroke locking plate is disposed above and parallel to the top wall. Passing through the top wall is an adjustment locking rod, including locking means to lock said locking rod at desired locations. A cylinder stroke adjuster disc is adjustably held by said locking rod and defines a stroke limit within the outer housing cylinder. Connected to the outside of said piston assembly is an outer piston disc and this piston disc moves longitudinally within said outer housing cylinder between the stroke adjuster disc and bottom wall. The outer piston disc is activated by a pneumatic arrangement feeding compressed air to the outer piston disc through the stroke adjuster disc. Thus, the outer piston disc provides a first stroke and the impact piston provides a second stroke, the length and quantity of air fed to the first stroke being adjustable 7 LP xsegem w l l" as s a a? V /l K /f m Q 28 i I 4 l I 6 7: {A L 2 2 Li J 34 ,AIZ

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2 Sheets-Sheet 1 FIG.

Bywwy rowan PRESS BACKGROUND OF THE INVENTION The present invention relates to pneumatic power press tools and more particularly to a ram-type press tool wherein the gas volume for the down stroke is metered in direct relationship to the length of the stroke.

A conventional cylinder usually provides stroke adjustment solely through external devices. This means the volume of air entering the cylinder for the down stroke will never vary, regardless of the external stroke limitations. The present invention contemplates an arrangement wherein the volume of air is metered in direct relationship to the length of stroke. This provides the advantage over conventional cylinders of faster stroke action, due to decreased volume that must be expelled, and resultant increased efficiency of the entire unit because of the internally metered air supply.

SUMMARY OF THE INVENTION Generally speaking, the present invention contemplates a pneumatic power press tool having an elongated cylindrical piston assembly having an upper impact air port at the upper end of said assembly and an impact piston within said assembly, acted upon by compressed air fed through said impact air port. There is an outer housing cylinder with said assembly being radially disposed and longitudinally displaceable therein. A cylinder stroke locking plate is disposed above and parallel to the top wall. Passing through the top wall is an adjustment locking rod, including locking means to lock said locking rod at desired locations. A cylinder stroke adjuster disc is adjustably held by said locking rod and defines a stroke limit within the outer housing cylinder. Connected to the outside of said piston assembly is an outer piston disc, and this piston disc moves longitudinally within said outer housing cylinder between the stroke adjuster disc and bottom wall. The outer piston disc is activated by a pneumatic arrangement feeding compressed air to the outer piston disc through the stroke adjuster disc. Thus, the outer piston disc provides a first stroke and the impact piston a second stroke, the length and quantity of air fed the first stroke being adjustable.

BRIEF DESCRIPTION OF THE DRAWINGS The invention as well as other objects and advantages thereof will be more readily understood from the following detailed description when considered together with the accompanying drawings, in which:

FIG. I is a sectional view of the inventive concept with the tool adjusted for a particular length stroke; and

FIG. 2 shows a sectional view similar to FIG. I, but with the tool adjusted for another length.

DETAILED DESCRIPTION The tool has a housing cylinder 12 with a ram and piston assembly 14 therein. Cylinder 12 has top and bottom walls I6, 18. Over top wall 16 and parallel to the top wall is a cylinder stroke locking plate 20, which is kept in place by spacers 22 with threaded ends passing appropriate apertures in the cylinder stroke locking plate 20, the plate being bolted to the spacers.

The top wall 16 has rod apertures 24 therein for the passage of adjustment locking rods 26. These adjustment locking rods 26 pass through the cylinder stroke locking plate 20 and are bolted thereto by locking nuts 28. The adjustment rod 26 can be adjusted vertically by releasing the locking nuts 28 and vertically moving the adjustment locking rods.

The cylinder stroke locking rods 26 support a cylinder stroke adjuster disc 30. This disc has a diameter corresponding to the cylinder inner diameter and can move up and down vertically by moving the cylinder stroke locking rods 26. Cylinder stroke adjuster disc 30 has an air outlet 32 to which is connected an air pipe 34. This air pipe 34 also passes through the top wall and the cylinder stroke locking plate, and has a down stroke air port 36 well above the cylinder.

The ram and piston assembly 14 generally comprises an outer piston disc 38, a hollow cylindrical piston 40, an inner impact piston 42, an impact piston return spring 44, an outer tool retaining piston'cap 46, with an upper impact air port 48, and a lower impact exhaust port 50. Outer piston disc 38 is attached to cylindrical piston 40 and will move between the cylinder stroke adjuster disc 30 and bottom wall 18. Bottom wall 18 has an up stroke air port 52. To properly seal off the various parts of the cylinder, cylinder stroke adjustment disc, ete., O-ring seals are provided. Also to protect the outer piston disc 38, upper and lower cushions 54, 56 are provided.

OPERATION OF THE D EVICE The tool operates in two strokes, the stroke provided by the outer piston disc 38 and the stroke provided by the inner impact piston 42. The inner impact piston stroke is fixed, while the outer stroke is adjustable.

To make a stroke adjustment, which actually limits the return travel of the piston, it is necessary to: a) release locking nuts on adjustment locking rods; b) exert slight physical pressure on exposed locking rods to move cylinder stroke adjuster disc vertically to position desired; c) bring locking nuts firmly against the cylinder stroke locking plate and lock.

The air inlet (down stroke) part is an intergral part of the cylinder stroke adjuster disc by means of the air pipe. This pipe and also the adjustment locking rods which are secured to the adjuster disc slide freely through the top wall of the cylinder.

The impact piston is activated by a sudden flow of air released through a three-way valve 54 having an exhaust port to expel spent air. This valve 54 is mounted just before the impact air port and is a catalog item, commercially available. The impact piston is then propelled rapidly toward the tool retaining piston cap. Not shown in the drawing is a custom tool for a specific job, e.g., staking, flaring, etc. The piston strikes the top of this special tool, expending all its velocity force on impact. The resultant impact force transmits thru the tool to the work piece.

It is to be observed therefore, that the present invention provides for an improvement in a pneumatic power press tool of the type having an elongated cylindrical piston assembly 14 with upper and lower ends and having an upper impact air port 48 at the upper end of the piston assembly, an impact piston 42 within the piston assembly, acted upon by com pressed air fed through said impact air port, an impact return spring 44 towards the lower end of the piston assembly and an impact exhaust port 50 towards the lower end of the piston assembly. The improvement herein contemplated serves to meter the stroke length and the amount of air fed to the tool. This is accomplished by having an outer housing cylinder 12 with said piston assembly 14 being radially disposed therein, the housing has top and bottom walls I6, I8 with apertures 24 so that the piston assembly 14 is longitudinally displaeeable in the housing. Disposed above and parallel to said top wall 16 is a cylinder stroke locking plate 20, including spacer means 22 firmly holding said locking plate 20 in a selected position. There is at least one adjustment locking rod 26, passing through said top wall 16, including locking means to lock the locking rod to the cylinder stroke locking plate 20. A cylinder stroke adjuster disc 30 is adjustably held by said locking rod 26, defining a stroke limit within said outer housing cylinder 12. An outer piston disc 38 is connected to the outside of the piston assembly 14 said piston disc 38 longitudinally moving within said outer housing cylinder 12 between stroke adjuster disc 30 and bottom wall 18. There is a separate pneumatic arrangement 34, 36, 52 for feeding compressed air to the outer piston disc 38 through stroke adjuster disc 30. Thus, outer piston disc 38 provides a first stroke and the impact piston 42 provides a second stroke, the length and quantity of air fed the first stroke being adjustable.

Although the present invention is described as a pneumatic tool. As is well known in the art, liquids may be used in lieu of gases so that the tool is really a fiuidic tool.

We claim:

1. In a fluidic power press tool of the type having an elongated cylindrical piston assembly (14) with upper and lower ends and having an upper impact fluid port (48) towards the upper end of said assembly, an impact piston (42) within said assembly, acted upon by compressed fluid fed through said impact fluid port, and an impact return spring (44) towards the lower end of said assembly, the improvement therein to meter the stroke length and the amount of fluid fed to the tool comprising in combination:

a. an outer housing cylinder (12) said assembly (14) being radially disposed therein;

b. top and bottom walls (16, 18) with apertures (24) said assembly (14) being longitudinally displaceable therein;

0. a cylinder stroke locking plate (20) disposed above and parallel to said top wall (16) including spacer means (22) firmly holding said locking plate (20) in position;

d. at least one adjustment locking rod (26), passing through said top wall (16), including locking means to lock said locking rod to said cylinder stroke locking plate (20);

e. a cylinder stroke adjuster disc (30) adjustably held by said locking rod (26) defining a stroke limit within said outer housing cylinder (12);

f. an outer piston disc (38) connected to the outside of said piston assembly (14) said piston disc (38) longitudinally moving within said outer housing cylinder (12) between said stroke adjuster disc (30) and said bottom wall (18); and,

g. a fluidic arrangement (34, 36, 52) for feeding compressed fluid to said outer piston disc (38) through said stroke adjuster disc (30), including a pipe passing through said top wall (16) and cylinder stroke adjuster disc (30) to supply compressed fluid to said piston disc, and an up stroke port in said bottom wall (18), whereby said outer piston disc (38) provides a first stroke and said impact piston (42) a second stroke, the length and quantity of fluid fed said first stroke being adjustable.

Hum" NU 

1. In a fluidic power press tool of the type having an elongated cylindrical piston assembly (14) with upper and lower ends and having an upper impact fluid port (48) towards the upper end of said assembly, an impact piston (42) within said assembly, acted upon by compressed fluid fed through said impact fluid port, and an impact return spring (44) towards the lower end of said assembly, the improvement therein to meter the stroke length and the amount of fluid fed to the tool comprising in combination: a. an outer housing cylinder (12) said assembly (14) being radially disposed therein; b. top and bottom walls (16, 18) with apertures (24) said assembly (14) being longitudinally displaceable therein; c. a cylinder stroke locking plate (20) disposed above and parallel to said top wall (16) including spacer means (22) firmly holding said locking plate (20) in position; d. at least one adjustment locking rod (26), passing through said top wall (16), including locking means to lock said locking rod to said cylinder stroke locking plate (20); e. a cylinder stroke adjuster disc (30) adjustably held by said locking rod (26) defining a stroke limit within said outer housing cylinder (12); f. an outer piston disc (38) connected to the outside of said piston assembly (14) said piston disc (38) longitudinally moving within said outer housing cylinder (12) between said stroke adjuster disc (30) and said bottom wall (18); and, g. a fluidic arrangement (34, 36, 52) for feeding compressed fluid to said outer piston disc (38) through said stroke adjuster disc (30), including a pipe passing through said top wall (16) and cylinder stroke adjuster disc (30) to supply compressed fluid to said piston disc, and an up stroke port in said bottom wall (18), whereby said outer piston disc (38) provides a first stroke and said impact piston (42) a second stroke, the leNgth and quantity of fluid fed said first stroke being adjustable. 